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Effect of processing parameters on the electromagnetic radiation emission during plastic deformation and crack propagation in copper-zinc alloys
KUMAR Rajeev, MISRA Ashok
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2006, 7(11): 3-.
https://doi.org/10.1631/jzus.2006.A1800
This paper presents some investigations on the effect of processing parameters on the emission of electromagnetic radiation (EMR) during plastic deformation and crack propagation in copper-zinc alloys. Timing of the EMR emissions, maximum stress during crack instability, stress-intensity factor, elastic strain energy release rate, maximum EMR amplitude, RMS value of EMR amplitude, EMR frequency and electromagnetic energy release rate were analysed for the effect of rolling directions at different percentage of zinc content in Cu-Zn alloy specimens. The same parameters were also analysed for 68-32 Cu-Zn alloy specimens at different annealing temperatures and at different angles θ, to the rolling direction. EMR emissions are observed to be highly anisotropic in nature. At θ=45° to 60°, marked changes in mechanical and electromagnetic parameters were observed. Specimens annealed at 500 °C, just above the recrystallization temperature, and at 700 °C, when grain-size growth is rapid, EMR responses have been found to have well-defined patterns.
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3DTS: A 3D tolerancing system based on mathematical definition
CAO Yan-long, LIU Yu-sheng, MAO Jian, YANG Jiang-xin
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2006, 7(11): 4-.
https://doi.org/10.1631/jzus.2006.A1810
Tolerance is almost ubiquitous during the whole product lift cycle and is imperative for seamless integration of CAD and CAM. Based on the mathematical definition of tolerance, a 3D tolerancing system, 3DTS, is presented with its design principle, system architecture and key functions. The following functional modules, tolerance modeling, semantics interpretation, 3D tolerance analysis, are described in detail. To make the tolerancing system robust and efficient, many techniques such as hierarchical tolerance representation, rule-based evaluation and non-intersection determination of tolerance zone have been devised. Tested by many samples, this system shows good robustness and practicability.
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Study on the applicability of frequency spectrum of micro-tremor and dynamic characteristics of surface ground in Asia area
CHE Ai-lan, IWATATE Takahiro, ODA Yoshiya, GE Xiu-run
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2006, 7(11): 9-.
https://doi.org/10.1631/jzus.2006.A1856
The dynamic characteristics of ground soil using micro-tremor observation in Asia (Zushi and Ogasawara (Japan), Xi’an (China), Manila (Philippines), and Gujarat (India)) are studied. Ground micro-tremor signals were observed and analyzed by fast Fourier transform method (FFT). The response of ground soil to frequency of ground micro-tremor is revealed, and functions with frequency-dependence and frequency-selection of micro-tremor for different foundation soil strata are also researched. The horizontal to vertical spectral ratio (H/V, Nakamura technique) of micro-tremor observed at the surface ground was used to evaluate the site’s predominant period. This paper also discusses the application of micro-tremor on site safety evaluation, and gives the observed calculation results obtained at multiple points. The experimental foundation and the deduction process of the method are described in detail. Some problems of the method are pointed out. Potential use of the technique’s good expandable nature makes it a useable means for preventing and reducing disaster’s harmful effects.
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Removal of PCDDs/Fs from municipal solid waste incineration by entrained-flow adsorption technology
YAN Jian-hua, PENG Zheng, LU Sheng-yong, LI Xiao-dong, CEN Ke-fa
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2006, 7(11): 14-.
https://doi.org/10.1631/jzus.2006.A1896
Entrained flow adsorption using activated carbon as the adsorbent is widely adopted for PCDDs/Fs-abatement in municipal solid waste incineration (MSWI) process. The effects of operating parameters including flue gas temperature, feeding rate of activated carbon, polychlorinated dibenzodioxins and polychlorinated dibenzofurans (PCDDs/Fs) concentration at the inlet of the air pollution control device (APCD), filter materials, pressure drop on PCDDs/Fs removal efficiency are reviewed and commented upon in this paper. Evaluation on the various mechanistic models for entrained flow adsorption is carried out based on the computational simulation in terms of the actual operating condition and theoretical analysis. Finally, an advancement of entrained flow adsorption in combination of dual bag filter is introduced.
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The fracture network model of Shen 229 block buried hill: A case study from Liaohe Basin, China
XING Yu-zhong, FAN Tai-liang, ZHENG Li-hui
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2006, 7(11): 15-.
https://doi.org/10.1631/jzus.2006.A1904
High oil production from the Proterozoic formation of Shen 229 block in Damingtun Depression, Liaohe Basin, China, indicates the presence of natural fractured reservoir whose production potential is dominated by the structural fracture. A consistent structural model and good knowledge of the fracture systems are therefore of key importance in reducing risk in the development strategies. So data from cores and image logs have been collected to account for the basic characteristics of fracture, and then the analyzed results were integrated with the structural model in order to restrict the fracture network development during the structural evolvement. The structural evolution of the Proterozoic reservoir with time forms the basis for understanding the development of the 3D fracture system. Seismic interpretation and formation correlation were used to build a 3D geological model. The fault blocks that compose the Proterozoic formation reservoir were subsequently restored to their pre-deformation. From here, the structures were kinematically modeled to simulate the structural evolution of the reservoirs. At each time step, the dilatational and cumulative strain was calculated throughout the modelling history. The total strain which records the total spatial variation in the reservoir due to its structural history, together with core data, well data and the lithology distribution, was used to simulate geologically realistic discrete fracture networks. The benefit of this technique over traditional curvature analysis is that the structural evolution is taken into account, a factor that mostly dominates fracture formation.
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Assessment of semi-empirical mass transfer correlations for pervaporation treatment of wastewater contaminated with chlorinated hydrocarbons
LIU Sean X., PENG Ming
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2006, 7(11): 16-.
https://doi.org/10.1631/jzus.2006.A1911
Assessment of mass transfer characteristics of pervaporation (PV) treatment of wastewater contaminated with chlorinated hydrocarbons is of great importance for water treatment plant operators conducting initial evaluation, process optimization, and process economics. While a membrane plays a central role in pervaporation processes and separation efficiency, the mass transfer in the liquid layer next to the membrane surface is of equal, if not greater importance. It is one of the few process parameters that can be adjusted in situ to manipulate the outcome of a pervaporation process. In this study, a bench scale pervaporation experiment of removing a common chlorinated hydrocarbon from water was carried out and the results of it were compared to the ones based on well-known semi-empirical correlations. The mass transfer coefficients from the experiments, ranging from 0.8×10−5~2.5×10−5 m/s under the operating conditions, are higher than those predicted by the correlation. The corresponding separation factors under varying flow velocities are determined to be between 310~950.
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Enhancement of the thermostability of β-1,3-1,4-glucanase by directed evolution
ZHANG Xiu-yan, RUAN Hui, MU Lin, HE Guo-qing, TANG Xing-jun, CHEN Qi-he
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2006, 7(11): 22-.
https://doi.org/10.1631/jzus.2006.A1948
In order to improve the thermostability of β-1,3-1,4-glucanase, evolutionary molecular engineering was used to evolve the β-1,3-1,4-glucanase from Bacillus subtilis ZJF-1A5. The process involves random mutation by error-prone PCR and DNA shuffling followed by screening on the filter-based assay. Two mutants, EGs1 and EGs2, were found to have four and five amino acid substitutions, respectively. These substitutions resulted in an increase in melting temperature from Tm=62.5 °C for the wild-type enzyme to Tm=65.5 °C for the mutant EGs1 and 67.5 °C for the mutant EGs2. However, the two mutated enzymes had opposite approaches to produce reducing sugar from lichenin with either much higher (28%) for the former or much lower (21.6%) for the latter in comparison with their parental enzymes. The results demonstrate that directed evolution is an effective approach to improve the thermostability of a mesophilic enzyme.
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An appraisal of techniques and equipment for cutting force measurement
AUDY J.
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2006, 7(11): 1781-1789.
https://doi.org/10.1631/jzus.2006.A1781
Current research focussed on the assessment of metal machining process parameters and on the development of adaptive control, shows that machine performance, work-piece and tool material selections, tool life, quality of machined surfaces, the geometry of cutting tool edges, and cutting conditions are closely related to the cutting forces. This information is of great interest to cutting tool manufactures and users alike. Over the years there have been significant developments and improvements in the equipment used to monitor such forces. In 1930 mechanical gauges were replaced by resistance strain gauges, and some 30 years later compact air gauge dynamometers were invented. Since this time intensive research has continued being directed towards developing new approaches to cutting force measurement. The Kistler Company, well-known manufacturer of acceleration and piezoelectrical dynamometers, has worked in this field for more than three decades, and developed very sensitive devices. While leading manufacturing research laboratories are often equipped with this technology, classical electrical strain gauges and other dynamometers of individual designs are still commonly used in industry. The present paper presents data obtained using different techniques of force measurement in metal machining processes. In particular, areas of uncertainties, illustrated through results concerning the turning process, are analysed, leading to an appraisal of the current status of these measurements and their significance.
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Performance evaluation of minimum quantity lubrication by vegetable oil in terms of cutting force, cutting zone temperature, tool wear, job dimension and surface finish in turning AISI-1060 steel
KHAN M.M.A., DHAR N.R.
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2006, 7(11): 1790-1799.
https://doi.org/10.1631/jzus.2006.A1790
In all machining processes, tool wear is a natural phenomenon and it leads to tool failure. The growing demands for high productivity of machining need use of high cutting velocity and feed rate. Such machining inherently produces high cutting temperature, which not only reduces tool life but also impairs the product quality. Metal cutting fluid changes the performance of machining operations because of their lubrication, cooling and chip flushing functions, but the use of cutting fluid has become more problematic in terms of both employee health and environmental pollution. The minimization of cutting fluid also leads to economical benefits by way of saving lubricant costs and workpiece/tool/machine cleaning cycle time. The concept of minimum quantity lubrication (MQL) has been suggested since a decade ago as a means of addressing the issues of environmental intrusiveness and occupational hazards associated with the airborne cutting fluid particles on factory shop floors. This paper deals with experimental investigation on the role of MQL by vegetable oil on cutting temperature, tool wear, surface roughness and dimensional deviation in turning AISI-1060 steel at industrial speed-feed combinations by uncoated carbide insert. The encouraging results include significant reduction in tool wear rate, dimensional inaccuracy and surface roughness by MQL mainly through reduction in the cutting zone temperature and favorable change in the chip-tool and work-tool interaction.
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23 articles
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